Method of forming connecting rods



Dec. 1s, 1934. w. H BAGLEY 1,984,624

METHOD OF FORMING CONNEGTIG RODS Filed June 15, 19:51

PV l

:lll Il ATTORN EYfG Patented Dec. il@9 i934 @TTS PATENT @FFME Bohn Aluminum & Brass Corporation,

Detroit,

Mich., a corporation of Michigan Application .lune l5, 11931, Serial No. 544,671

2 Claims.

The relates to connecting rods invention formed of metals or alloys having a relatively low specific gravity, such for instance as aluminum alloy. In the present state of the art it is usual in the manufacture of such rods to heat treat the same so as to improve their physical characteristics. It is also customary to line the bearing apertures with babbitt and to insure the bond ing of this babbitt with the body of the rod, the contacting surface of the latter is tinned. It is difficult, however, to cause the tin to adhere to the surface of the rod due to the fact that an exposed face of aluminum is very quickly coated with oxide to which the tin will not adhere. It has therefore been the usual practice to immerse the journal portion of the rod in a molten bath of tin and while in this bath to brush or scrub the surface of the bearing until the oxide is removed therefrom, so that the tin will adhere. Such treatment is highly detrimental in that the desirable physical properties which have been imparted to the rod by the previous heat treatment will be lost due to the reheating of therod in the tinning bath.

It is the object of the present invention to tin the surface of the rod without raising the temperature thereof to a degree which will be detrimental to the physical properties acquired by a previous heat treatment. To this end the invenv tion consists in the method as hereinafter set forth.

In the drawing: Figure l is a diagrammatic elevation illustrating the brushing of the bearing prior to tinnng;'

Figure 2 is a similar view illustrating the brushing in the tinning bath.

In carrying out my improved process the machined rod before being immersed in the tinning bath is subjected to a brushing action on the surface to which the tin is to adhere. 'I'his is preferably accomplished as shown by means of a rotary wire brush A which is arranged adjacent to the tinning bath so that the operator can rst thoroughly brush the inner surface of the journal aperture in the rod and then immediately plunge it into the tinning bath. The brush used for this treatment is somewhat coarser than that which (Gl. fill-70.2)

is generally used for brushing in the tin bath and I have found that in addition to removing a considerable amount of the oxide from the surface it also abradesor grooves the surface so as to increase the adhesion between the same and the babbitt lining subsequently applied as indicated at B. However, this pre-brushing I have found is insuicient to cause a complete tinning of the surface and must be supplemented by a brushing with a finer brush C while the rod is immersed in the tin in the bath D which brings the molten metal in intimate contact with the roughened surface. This latter step can be accomplished in a comparatively short time interval so that the temperature of the rod while remaining in the bath will not rise to a detrimental point. After removing the rod from the bath it is babbitted by any suitable process and the tinnedsurface together with the abrasion formed by the rst brushing will' cause rm adhesion of the babbitt.

What I claim as my invention is:

1. The method of tinning surfaces of metallic members which have been previously heat treated to improve their physical characteristics comprising brushing said surfaces with a brush of suincient coarseness to remove the oxide and abrade the surface, immediately plunging the brushed surfaces into a bath of molten tin, further brushing the surfaces while bathed with tin but only for a time interval too short to be detrimental to the physical properties obtained by the heat treatment, and removing the article from the bath.

2. The method of tinning surfaces of aluminum members which have been previously heat treated to improve their physical characteristics compris# ing brushing said surfaces with a brush of sulficient coarseness to remove the oxide and abrade the surface, immediately plunging the brushed surfaces into a bath of molten tin, further brushing the surfaces while bathed with tin but only for a time interval too shcrtto be detrimental to the physical properties obtained by the heat treatment, and removing the article from the bath.

WILLIAM I-I. BAGLEY. 

